Stabberless Elevator Assembly with Spider Interlock Control

ABSTRACT

A collar locating assembly ensures that that an elevator slip assembly does not engage against a pipe collar or coupling. An interlock system controls the operation of elevator slips, as well as related spider slips, in order to prevent unwanted simultaneous disengagement of both elevator and spider slips.

CROSS REFERENCES TO RELATED APPLICATION

PRIORITY OF U.S. PROVISIONAL PATENT APPLICATION Ser. No. 61/664,236, FILED Jun. 26, 2012, INCORPORATED HEREIN BY REFERENCE, IS HEREBY CLAIMED.

STATEMENTS AS TO THE RIGHTS TO THE INVENTION MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

NONE

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a method and apparatus for ensuring that an elevator slip assembly does engage against a pipe collar or coupling. More particularly, the present invention further pertains to an interlock system to control the operation of elevator slips, and any related spider slips, in order to prevent unwanted simultaneous disengagement of both elevator and spider slips.

2. Brief Description of the Prior Art

Oil and gas operations frequently involve the use of pipe and/or other tubular goods manipulated from a surface drilling rig or other surface facility. Such tubular goods are usually inserted into a well in a number of separate sections of substantially equal length called “joints.” Such joints are typically screwed together or otherwise joined end-to-end at the rig floor of a drilling rig in order to form a substantially continuous “string” of pipe that reaches downward into the earth's crust. As the bottom or distal end of the pipe string extends further into a well, additional sections of pipe are added to the upper end of the pipe string at said drilling rig.

The process of installing a string of pipe in a well is typically commenced by lowering a first section of pipe into a wellbore at a drilling rig floor, and suspending said section of pipe in place using a lower gripping apparatus commonly referred to as “spider slips”. In this position, the uppermost end of said first section of pipe is generally situated a desired distance above the rig floor. Thereafter, a second section of pipe is lifted within a drilling rig derrick and suspended vertically within said derrick. Said second section of pipe is then positioned in linear alignment above the first section of pipe (which was previously run into the well and is being gripped by said spider slips). The lower end of said second pipe section is then connected to the upper end of said first pipe section.

After said sections of pipe have been joined together (typically using a threaded connection), a vertically movable upper gripping assembly, commonly referred to as “elevator slips”, is lowered around the upper end of such joined pipe sections. Once said elevator slips are properly positioned and latched around the body of the pipe, said elevator slips can be raised, thereby taking weight off of the lower spider slips. In this configuration, the lower spider slips can then be disengaged, allowing the entire weight of the pipe string to be suspended from said elevator slips. The joined sections of pipe can then be lowered into the well by lowering said elevator slips a desired distance before engaging the spider slips. This process is repeated until a desired length of pipe (i.e., the desired number of pipe sections) is inserted into the wellbore.

At certain points during this pipe installation process, the entire weight of the pipe string is being held or suspended by the elevators and, more specifically, the elevator slips. Such pipe string can be very heavy, especially when many joints of large diameter and/or heavy-wall casing are being run into a well. Accordingly, it is extremely important that said elevator slips must be properly engaged around the uppermost section of pipe in the derrick to ensure that such pipe remains securely gripped by said elevators. If the pipe is not properly gripped by such elevator slips, it is possible that the pipe could drop or fall out of the elevators, thereby causing damage to the rig or the well, or injury to rig personnel.

In many cases, pipe sections are joined together using internally threaded couplings having a larger outer diameter than the adjoining pipe body section. Care must be taken to ensure that elevator slips, which are designed to engage against the outer surface of a pipe body, are actually aligned with said pipe body and not a coupling. If such elevator slips are inadvertently closed against a coupling, such elevator slips likely will not fully contact or engage against the outer surface of the pipe and may not grip the pipe securely. As a result, such improperly set elevator slips may not be able to support the weight of the pipe string, allowing such pipe to fall out of the elevator slips and into the wellbore below.

Historically, personnel have frequently been stationed in an elevated position within a drilling rig derrick (such as on a board or the like) in order to assist with the pipe connection and running processes. In one common method of installing or running pipe into a wellbore, a worker is stationed on a platform in the derrick at approximately the height where elevator slips are closed on the top of a section of pipe, which can often be approximately forty (40′) feet or more above the rig floor. The worker, often referred to as a “derrick man,” would visually observe when elevator slips have been sufficiently lowered over the top of a section of pipe and properly positioned relative to said section of pipe (and any collar attached to the uppermost end thereof).

Numerous automated devices have been developed to assist with the alignment and interconnection of joints of elongated pipe and other tubular goods used in the drilling and completion of oil and gas wells in order to eliminate the need for personnel to work at elevated locations with a derrick. Conventional stabber-less elevator assemblies can often eliminate the need for stationing personnel within a derrick. However, such conventional assemblies generally cannot detect when an elevator has progressed to a correct position relative to a pipe collar, such that elevator slips will not attempt to engage against a collar (instead of the pipe body itself).

Thus, there is a need for an elevator assembly that prevents elevator slips from setting on a collar, while providing confirmation that such elevator slips are actually set on a pipe body itself (and not a collar). Said elevator assembly can further include an interlock control system to control the operation of said elevator slips, and any associated spider slips, in order to prevent unwanted simultaneous disengagement of both elevator slips and spider slips (which could result in inadvertent dropping of a pipe string).

SUMMARY OF THE INVENTION

In the preferred embodiment, the present invention comprises a stabbing assembly comprising substantially planar plate member having a central bore or aperture. When attached to a set of slip-type elevators, said central bore or aperture is positioned in alignment with the central bore of said elevators. At least one cylinder is connected to said plate member; in the preferred embodiment, two cylinders are employed and positioned generally lateral to said elevators. Said cylinders, which can be hydraulically or pneumatically actuated, can be extended or retracted in a substantially axial direction (that is, parallel to the path of travel of such elevator elevators). Further, such cylinders can be simultaneously or independently actuated to adjust the positioning of any pipe connected to said cylinders.

When utilized in connection with conventional slip-type elevators, the apparatus of the present invention can be used to pull a joint of pipe upward into mating relationship with a nose of a fill-up tool, stabbing connection or the like. At that point, said slip-type elevators can be lowered over the pipe in order to grip said pipe. Although the present invention can be utilized during the installation of casing, it is to be observed that the present invention can be used with virtually any tubular good including, without limitation, production tubing or the like.

Spaced-apart collar locator fingers are disposed at or near the upper surface of said elevator assembly. In the event that a collar contacts said spaced-apart collar locator fingers as an elevator assembly is lowered over such pipe section, said collar will force said collar locator fingers upward to a pre-determined position. In such position, a valve shifts which permits fluid pressure to communicate with an indicator or alarm (ideally positioned on a central control panel), signaling to an operator that said collar is in correct position relative to the slip members of said elevator assembly.

Further, an interlock control system controls the operation of said elevator slip assembly and an associated spider slip assembly, and beneficially prevents unwanted simultaneous disengagement of both elevator slips and spider slips from pipe which could result in inadvertent dropping of such pipe. Although said interlock control system can be arranged in many different configurations, in a preferred embodiment said control system is at least partially housed within an operator console that can be beneficially placed at a convenient location such as on a rig floor or other area in proximity and line-of-sight to pipe running operations.

BRIEF DESCRIPTION OF DRAWINGS/FIGURES

The foregoing summary, as well as any detailed description of the preferred embodiments, is better understood when read in conjunction with the drawings and figures contained herein. For the purpose of illustrating the invention, the drawings and figures show certain preferred embodiments. It is understood, however, that the invention is not limited to the specific methods and devices disclosed in such drawings or figures.

FIG. 1 depicts a side schematic view of an elevator slip assembly, spider slip assembly and control system of the present invention.

FIG. 2 depicts a side schematic and partial sectional view of an elevator slip assembly of the present invention.

FIG. 3 depicts a side schematic and partial sectional view of a spider slip assembly of the present invention.

FIG. 4 depicts a schematic view of an interlocking control cabinet of the present invention.

FIG. 5 depicts a rear view of an elevator slip assembly of the present invention.

FIG. 5 a depicts a detailed view of a highlighted area depicted in FIG. 5.

FIG. 6 depicts a side view of an elevator slip assembly of the present invention.

FIG. 6 a depicts a detailed view of a highlighted area depicted in FIG. 6.

FIG. 7 depicts a perspective view of certain components of an elevator slip assembly of the present invention.

FIG. 8 depicts a side view of certain components of an elevator slip assembly of the present invention.

FIG. 8 a depicts a detailed view of a highlighted area depicted in FIG. 8.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 depicts a side schematic and partially sectional view of a stabber-less elevator slip assembly 100, spider slip assembly 200 and interlock control assembly 300 of the present invention. As depicted in FIG. 1, said elevator slip assembly 100 is shown gripping against a section of pipe 400, while spider slip assembly 200 is shown gripping against a section of pipe 410. As discussed herein, pipe sections 400 are depicted as joints of casing equipped with collars 401 and 411, respectively; however, it is to be observed that said pipe sections can be virtually any tubular good including, without limitation, production tubing or the like.

Still referring to FIG. 1, interlock control system 300 controls the operation of elevator slip assembly 100 and spider slip assembly 200, and beneficially provides an interlock system to prevent unwanted simultaneous disengagement of both elevator slips and spider slips from pipe joints 400 and 410 (which could result in inadvertent dropping of a pipe string). Although said interlock control system 300 can be arranged in many different configurations, in a preferred embodiment said control system 300 is housed within an operator console that can be beneficially placed at a convenient location such as on a rig floor or other area in proximity and/or line-of-sight to pipe installation operations.

In a preferred embodiment, interlock control system 300 comprises a pneumatic control system having a plurality of tubular control lines, valves and related components. Fluid (air) pressure is supplied to said pneumatic control system using air source 310, which can be an air compressor, blower or drilling rig air supply. It is to be observed that said interlock control system can also be configured using hydraulic control lines, valves and components, electrical and/or wireless communication control means and components, or a combination of some or all.

FIG. 2 depicts a side schematic and partial sectional view of an elevator slip assembly 100 of the present invention. As depicted in FIG. 2, elevator body 101 has a central bore 102 extending through said elevator body member 101. Said elevator assembly 100 is suspended from bails (not shown in FIG. 2), which are in turn connected to a movable top drive unit or traveling block of a drilling rig in a manner that is well known to those having skill in the art. A fluid fill-up tool 500 is connected to said top drive unit (not depicted in FIG. 1) to permit drilling mud or other fluids to flow through said top drive unit, said fill-up tool and, ultimately, into the internal bore of pipe section 400. Both said elevator assembly 100 and fill-up tool 500 can move together in unison as a top drive unit moves up or down within a drilling rig derrick.

As depicted in FIG. 2, central through bore 101 of elevator assembly has at least one tapered shoulder surface 103 defining an internal slip bowl profile. Slip members 104 are moveably disposed on said at least one tapered surface 103 within elevator body member 101, such that said slip members 104 can travel along said at least one tapered surface 103. Gripping slip dies 104 a can be disposed on the inwardly facing surface(s) of slip members 104. When gripping of a section of pipe disposed within central bore 102 (such as pipe section 400 in FIG. 2) is desired, downward force can be applied to slip members 104. Said slip members 104 travel along tapered surface(s) 103, which in turn forces said slip members 104 radially inward, causing gripping slip dies 104 a to engage in gripping relationship against the external surface of pipe section 400. The greater the axial downward force applied to slip members 104, the greater the gripping force exerted on pipe section 400.

As depicted in FIG. 2, casing fill-up tool 500 is partially received within the upper end of pipe joint 400, which is gripped by elevator assembly 100 (and, more specifically, slip members 104). Said casing fill-up tool 500, which operates in a manner well know to those having skill in the art, allows for filling of pipe sections with drilling mud or other fluid during casing installation operations.

Elevator assembly 100 further comprises a collar locator assembly. In the preferred embodiment, said collar locator assembly comprises base member 140 disposed on or near the upper surface of elevator body member 101. Housing member 142 is pivotally attached to said base member 140, and can be pivotally adjusted about bolt 141. Arm member 145 is slidably disposed within housing member 142 and can be secured in a desired position relative to housing member 142 using locking nut 143. Elongate rail member 144 is attached to said pivotal arm member 145, while bracket member 146 is slidably disposed on said elongate rail member 144.

Collar locating fingers 147 are pivotally mounted to bracket member 146. Spring 149 biases said collar locating fingers 147 against pivoting relative to said bracket member 146. Although not clearly visible in FIG. 2, collar locating fingers 147 comprise spaced apart, substantially parallel elongate finger members that extend, at least partially, over the upper opening of central through bore 102.

As noted above, elevator assembly 100 can be lowered over pipe section 400 as part of the pipe installation process. As collar 401 contacts spaced-apart collar locator fingers 147, said collar 401 forces said collar locator fingers 147 to pivot upward (resisting the force applied by bias spring 149). In the preferred embodiment, said spaced-apart collar locator fingers 147 can also separate or spread outwardly apart away from one another as said collar passes said collar locator fingers 147, thereby preventing said collar locator fingers 147 from breaking or being damaged by said collar 401. Said spaced-apart collar locator fingers 147 can further include a biasing spring to direct said collar locator fingers 147 inward toward each other when not in contact with a collar 401.

Still referring to FIG. 2, leveling arm 109 is pivotally attached to slip members 104; downward movement of said leveling arm 109 at slip members 104 causes elevator slip members 104 to be lowered into place until slip dies 104 a of said slip members 104 are engaged in gripping relationship with pipe section 400. Alternatively, upward movement of leveling arm 109 at slip members 104 lifts such slip members 104 until said slip dies 104 a are no longer engaged in gripping relationship against pipe section 400.

FIG. 3 depicts a side schematic and partial sectional view of a spider slip assembly 200 of the present invention having central through bore 201. As depicted in FIG. 3, central through bore 201 of spider assembly 200 has at least one tapered shoulder surface 203 defining an internal spider slip bowl profile. Slip members 204 are moveably disposed on said at least one tapered surface 203 within spider body member 201, such that said slip members 204 can travel along said at least one tapered shoulder surface 203.

Gripping slip dies 204 a can be disposed on the inwardly facing surface(s) of slip members 204. When gripping of a section of pipe disposed within central bore 102 (such as pipe section 410 in FIG. 3) is desired, downward force can be applied to slip members 204. Said slip members 204 travel along tapered shoulder surface(s) 203, which in turn forces said slip members 204 radially inward, causing gripping slip dies 204 a to engage in gripping relationship against the external surface of pipe section 410. The greater the axial downward force applied to said slip members 204, the greater the gripping force exerted on pipe section 410.

FIG. 4 depicts a side schematic view of an interlock control cabinet 300 of the present invention. Interlock control cabinet 300 generally comprises air filter/regulator 301, system pressure gauge 302, 2-position push-to-actuate air valve 303, 2-position, 4-way lever actuated air valve 304, air operated state change indicator 305, 2-position push-to-actuate air valve 306, 2-position, 4 way lever actuated air valve 307, and air operated state change indicator 308. In the preferred embodiment, interlock control cabinet 300 and all associated control lines, including pilot air supply line 126, are pneumatically operated using air pressure supplied by an air source 310.

FIG. 5 depicts a rear view of an elevator slip assembly 100 of the present invention, while FIG. 6 depicts a side sectional view of elevator slip assembly 100 of the present invention, rotated approximately 90-degrees from the view depicted in FIG. 5. Said elevator assembly 100 is suspended from bails 136, which are in turn connected to a movable top drive unit or traveling block of a drilling rig in a manner that is well known to those having skill in the art. A fluid fill-up tool 500 is connected to said top drive unit (not depicted in FIG. 5) to permit drilling mud or other fluids to flow through said top drive unit, said fill-up tool 500 and, ultimately, into the internal bore of pipe section 400.

Elevator assembly 100 further comprises an adjustable collar locator assembly located at or near the upper surface of elevator body member 101. Substantially parallel collar locating fingers 147 are pivotally mounted to said adjustable collar locator assembly and biased against upward pivoting. In the preferred embodiment, said substantially parallel collar locating fingers 147 can be beneficially spaced apart a predetermined distance, typically a distance that is greater than the outer diameter of fluid fill-up tool 500, but less than the outer diameter of collar 401.

As noted above, elevator assembly 100 can be lowered over the upper portion of a pipe section 400 as part of the pipe installation process. In the event that collar 401 contacts spaced-apart collar locator fingers 147, said collar 401 will force said collar locator fingers 147 to pivot in an upward direction. Once said collar locator fingers 147 have reached a pre-determined position, 3-way valve 148 shifts and allows control line fluid pressure to build. Such control line fluid pressure in turn causes a state indicator 305 (ideally positioned on an operator's panel on control cabinet 300, not depicted in FIG. 5 or 6) to change state, indicating to an operator that collar 401 is in correct position relative to slip members 104 of elevator assembly 100.

FIG. 5 a depicts a detailed view of a highlighted area depicted in FIG. 5. As noted above, when said slip members 104 are set and slip dies 104 a are properly engaged against pipe section 400 (and not on collar 401), slip location register 110 actuates valve 111 which, in turn, permits control line fluid pressure signal to be passed through a control line to a state change indicator 308 (ideally positioned on an operator's panel on control cabinet 300, not depicted in FIG. 5 a) signaling to an operator that said slips 104 are properly set against pipe section 400, and that further action in accordance therewith is justified.

FIG. 6 a depicts a detailed view of a highlighted area depicted in FIG. 6. As noted above, when said slip members 104 are set and slip dies 104 a are properly engaged against pipe section 400 (and not on collar 401), slip location register 110 actuates valve 111 which, in turn, sends a control line fluid pressure signal through control line 121 to a state change indicator as noted above, signaling to an operator that slips 104 are properly set against pipe section 400, and that further action is justified.

FIG. 7 depicts a perspective view of certain components of an elevator slip assembly of the present invention, while FIG. 8 depicts a side view of said elevator slip assembly of the present invention. In the preferred embodiment, the present invention comprises a substantially planar plate member 150 having a central bore or aperture 151. Said plate member 150 can be attached to a set of slip-type elevators, such that said central bore or aperture 151 is positioned in general alignment with the bore of said elevators (such as, for example, central bore 102 of elevator assembly 100 depicted in FIG. 2).

At least one cylinder 119 is connected to said plate member 150; in the preferred embodiment, two cylinders 119 are employed and positioned generally lateral to said central bore 151. Said cylinders 119, which can be hydraulically or pneumatically actuated, can be extended or retracted in a substantially axial direction. Further, such cylinders 119 can be simultaneously or independently actuated to adjust the positioning of pipe connected to said cylinders.

In the preferred embodiment, a collar locator assembly comprises base member 140 disposed on or near the upper surface of elevator body member 101. Housing member 142 is pivotally attached to said base member 140, and can be pivotally adjusted about bolt 141. Arm member 145 is slidably disposed within housing member 142 and can be secured in a desired position relative to housing member 142.

Elongate rail member 144 is attached to said pivotal arm member 145, while bracket member 146 is slidably disposed on said elongate rail member 144. Collar locating fingers 147 are pivotally mounted to bracket member 146. Springs 149 bias said collar locating fingers 147 against pivoting relative to said bracket member 146. Said collar locating fingers 147 comprise spaced apart, substantially parallel elongate members. In the preferred embodiment, said substantially parallel collar locating fingers 147 can be beneficially spaced apart a predetermined distance, typically a distance that is greater than the outer diameter of fluid fill-up tool 500, but less than the outer diameter of collar 401.

FIG. 8 a depicts a detailed view of a highlighted area depicted in FIG. 8. When collar locator fingers 147 pivot to a pre-determined position, 3-way valve 148 shifts, allowing control line fluid pressure to build. Such control fluid pressure in turn causes a state indicator (not depicted in FIG. 8, but ideally positioned on a control panel) to change state, indicating to an operator that collar locator fingers (and, therefore, a pipe collar) is in correct position to set slips against such pipe section.

In operation, a first section of pipe 410 and any related bottom hole assembly, tools or equipment can be inserted into a well and supported by spider slip assembly 200. Because the weight of said single joint and related tools/equipment is relatively light compared to a multi-joint pipe string, said initial pipe joint 410 can often be inserted into a well without gripping said initial pipe section using elevator assembly 100.

Referring to FIGS. 3 and 4, valve 303 begins a closed position. When setting of said spider slip assembly 200 on pipe section 410 is desired, an operator opens said valve 303 on control assembly 300. Control line fluid pressure passes through open valve 303 and line 224 to valve 217, which is a spring valve biased in the open position. Control line fluid pressure passes through said valve 217, as well as through control line 230, shuttle valve 215, pilot operated check valve 213 and control line 233. Said control line fluid pressure actuates cylinder 234, causing leveling arm 109 to pivot and slip members 204 to move radially inward and grippingly engage against the outer surface of pipe section 210.

When slip members 204 are grippingly engaged against pipe section 410, personnel at or near said spider slip assembly 200 (which is located at or near the rig floor) can typically visually or otherwise confirm that said slip members 204 are engaged against pipe section 410 and not collar 411. As such, slip location register 210 and related control lines and components depicted in FIG. 3, other than control line 224, are not typically utilized in such configuration, and are therefore depicted as blanked-off in FIG. 3. However, in the preferred embodiment, spider assembly 200 can be equipped with valve 211 and spider slip location register (having at least one elongate actuation finger member 210), as well as related control lines and valves, in the event that said spider assembly 200 is converted for use as an elevator assembly (such as in the event of malfunction or equipment damage).

An elevator assembly has at least one stabbing arm cylinder 119. Although not depicted in FIG. 2, in the preferred embodiment a cable or other flexible linkage member is attached to the distal/lower end of each such stabbing arm cylinder 119 that, in turn, can be attached to a single joint elevator apparatus well known to those having skill in the art. Said elevator assembly can be selectively lowered within a drilling rig derrick, allowing said single joint elevator to grip a loose section of pipe from a V-door, pipe rack or other accessible location.

Said elevator assembly can then be raised within a derrick which, in turn, raises said attached single joint elevator apparatus (as well as the gripped pipe section attached thereto) within said derrick. Thereafter, referring to FIG. 4, an operator can actuate a valve 304 on control panel 300 in order to supply air via line 135 to stabber arm cylinders 119. Although not depicted in the drawings, retraction of said stabber arm cylinders 119 raises said single joint elevator apparatus and a gripped section of pipe 400 toward said elevator assembly.

For purposes of this discussion, reference is generally made to FIGS. 2 through 4, with initial pipe section 410 already being gripped by spider assembly 200 and supported within a well bore. As single section of pipe 400 is raised toward elevator body 101 of elevator assembly 100, the distal end of fill-up tool 500 stabs within the upper opening of pipe section 400, aligning said pipe section 400 with bore 102 of elevator body 101 and fill-up tool 500. Once in this position, elevator body 101, fill-up tool 500 and pipe section 400 can all be lowered within a derrick until the lower end of pipe section 400 is in proximity with the upper end of pipe section 410 (gripped by a spider assembly 200).

Once pipe section 400 is threadably connected to pipe section 410 suspended from a spider assembly (typically using a power tong or other similar device), elevator body 101 can be further lowered over the upper end of pipe section 400. Simultaneously, fill-up tool 500 can extend deeper within the central bore of pipe section 400.

An operator can actuate lever valve 307 into the slip “set” position and actuate pushbutton-controlled valve 306 in order to supply fluid pressure to valve 307 which, in turn, allows control line fluid to flow through control line 125 to pilot operated 2-position, 4 way valve 116. Control fluid pressure is also being supplied through pilot line 126 and orifice 118 to a pilot port of valve 116. Such pilot pressure is also supplied to valve 148. When collar locator fingers 147 are in the lower position (indicating that collar 401 has not cleared said elevator assembly 100 a desired distance), valve 148 remains in the open position, allowing pilot fluid pressure to be vented or bled off; with valve 148 open and pilot fluid pressure being vented, pilot operated valve 116 remains in the closed position.

As said elevator body 101 is lowered over the upper end of pipe section 400, collar 401 will eventually protrude out of the upper opening of central bore 102 of said elevator body 101, making contact with collar locator fingers 147 and eventually causing said collar locator fingers 147 to pivot. When collar locator fingers 147 pivot to a pre-determined position (indicating positioning of collar 401 a desired distance above elevator assembly 100), valve 148 closes, allowing control line fluid pilot pressure to build. Such increased pilot line pressure in turn actuates pilot-operated valve 116.

Thereafter, control line fluid pressure passes through pilot operated valve 116, line 131, shuttle valve 115 and check valve 113. Said control line fluid pressure actuates cylinder 134, pivoting leveling arm 109 and setting slip members 104 to engage in gripping relationship with pipe section 400. Such increased fluid pressure also causes state indicator 305 (ideally positioned on an operator control assembly) to change state, indicating to an operator that collar 401 is in correct position relative to slip members 104 of elevator assembly 100.

Ball operated 3-position valve 111 remains in the closed position when slip members 104 are in the released position (that is, disengaged from pipe section 400, or incorrectly engaged against collar 401). However, when said slip members 104 are set and slip dies 104 a are properly engaged in gripping relationship against pipe section 400 and not on collar 401, slip location register of the present invention actuates valve 111; as depicted in FIG. 2, said slip location register comprises at least one elongate actuation member 110 attached to slip leveling arm 109. When valve 111 is opened, control line fluid pressure is sent through control line 121 to state change indicator 308 (not depicted in FIG. 2, but ideally positioned on a control panel) signaling to an operator that said slips 104 are properly set against pipe section 400.

Actuating state change indicator 308 indicates that slip members 104 are set in the correct position on pipe 400, thereby signaling to an operator that slip members 204 of spider assembly 201 can be opened. If said elevator slip members 104 happen to set against a collar 401, leveling arm 109 will not pivot to its predetermined position and will not allow valve 111 to shift. Under such a scenario, state change indicator 308 will not actuate, and will not signal an operator that it is safe to open slips 204 of spider assembly 200.

When slip members 104 of elevator assembly 100 have been set properly and an operator has received indication signal from state change indicator 308, said operator can actuate valve 303 to feed control line fluid pressure through line 224 to treadle operated valve 217 located on spider 201. At this point, said operator can actuate treadle-operated valve 217, allowing control line fluid pressure to be supplied through pilot-operated check 212 and to cylinder 234. This causes leveling arm 209 to pivot, raising spider slip members 204 and releasing the grip of said spider slip members 204 on said pipe. In this configuration, elevator assembly 100 is supporting the complete pipe/string weight; said pipe/string can be lowered to a desired level. Thereafter, spider slip assembly 200 can be set to grip said pipe string, and the process can be repeated so that additional pipe sections can be added to said pipe string.

The above-described invention has a number of particular features that should preferably be employed in combination, although each is useful separately without departure from the scope of the invention. While the preferred embodiment of the present invention is shown and described herein, it will be understood that the invention may be embodied otherwise than herein specifically illustrated or described, and that certain changes in form and arrangement of parts and the specific manner of practicing the invention may be made within the underlying idea or principles of the invention. 

What is claimed:
 1. An elevator assembly for gripping a section of pipe having a collar comprising: a) a body member having a central bore extending there through and defining a slip bowl; b) at least one slip member disposed within said slip bowl; and c) a collar locator assembly for signaling when the collar of said pipe is positioned a predetermined distance above said elevator assembly.
 2. The collar locator assembly of claim 1, wherein said collar locator assembly further comprises: a) a base disposed on said elevator assembly; and b) at least one finger member pivotally attached to said base and at least partially extending across the upper opening of said central bore of said elevator body member.
 3. The collar locator assembly of claim 2, further comprising a valve disposed beneath said at least one finger member, wherein said valve shifts when said at least one finger member pivots a predetermined distance.
 4. The collar locator of claim 3, wherein said at least one finger member comprises a pair of spaced apart and substantially parallel elongate finger members.
 5. The elevator assembly of claim 1, further comprising a slip location register for signaling when said at least one slip member is fully engaged in gripping position against said pipe.
 6. The elevator assembly of claim 5, wherein said slip location register further comprises: a) at least one elongate actuation member connected to a slip leveling arm; and b) a valve disposed beneath said at least one elongate actuation member, wherein said valve shifts when said slip leveling arm is in a predetermined position.
 7. A pipe gripping assembly comprising: a) an elevator assembly for gripping a first section of pipe having a collar comprising: i) a body member having a central bore extending there through and defining a slip bowl; ii) at least one slip member disposed within said slip bowl; and iii) a collar locator assembly for signaling when the collar of said pipe is positioned a predetermined distance above said elevator assembly; b) a spider assembly for gripping a second section of pipe having a collar comprising: i) a body member having a central bore extending there through and defining a slip bowl; ii) at least one slip member disposed within said slip bowl; and c) a control assembly for controlling said elevator assembly and said spider assembly.
 8. The pipe gripping assembly of claim 7, wherein said collar locator assembly further comprises: a) a base disposed on said elevator assembly; and b) at least one finger member pivotally attached to said base and at least partially extending across the upper opening of said central bore of said elevator body member.
 9. The pipe gripping assembly of claim 8, further comprising a valve disposed beneath said at least one finger member, wherein said valve shifts when said at least one finger member pivots a predetermined distance.
 10. The pipe gripping assembly of claim 9, wherein said at least one finger member comprises a pair of spaced apart and substantially parallel elongate finger members.
 11. The pipe gripping assembly of claim 7, further comprising an elevator slip location register for signaling when said at least one elevator slip member is fully engaged in gripping position against said pipe.
 12. The pipe gripping assembly of claim 13, wherein said elevator slip location register further comprises: a) at least one elongate actuation member connected to a slip leveling arm; and b) a valve disposed beneath said indexing member, wherein said valve shifts when said slip leveling arm is in a predetermined position.
 13. The pipe gripping assembly of claim 7, wherein said control assembly comprises an operator console.
 14. The pipe gripping assembly of claim 13, wherein said control assembly is pneumatically, hydraulically or electrically powered. 